Commit 53ebee94 authored by Linus Walleij's avatar Linus Walleij Committed by Jonathan Cameron
Browse files

iio: afe: iio-rescale: Support processed channels 

It happens that an ADC will only provide raw or processed
voltage conversion channels. (adc/ab8500-gpadc.c).
On the Samsung GT-I9070 this is used for a light sensor
and current sense amplifier so we need to think of something.

The idea is to allow processed channels and scale them
with 1/1 and then the rescaler can modify the result
on top.

Link: https://lore.kernel.org/linux-iio/20201101232211.1194304-1-linus.walleij@linaro.org/


Cc: Peter Rosin <peda@axentia.se>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: default avatarPeter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20210518092741.403080-1-linus.walleij@linaro.org


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 842b1722

drivers/iio/afe/iio-rescale.c

+35 −6
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ struct rescale { 
	struct iio_channel *source;

	struct iio_chan_spec chan;

	struct iio_chan_spec_ext_info *ext_info;

	bool chan_processed;

	s32 numerator;

	s32 denominator;

};
@@ -43,10 +44,27 @@ static int rescale_read_raw(struct iio_dev *indio_dev, 


	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		if (rescale->chan_processed)

			/*

			 * When only processed channels are supported, we

			 * read the processed data and scale it by 1/1

			 * augmented with whatever the rescaler has calculated.

			 */

			return iio_read_channel_processed(rescale->source, val);

		else

			return iio_read_channel_raw(rescale->source, val);



	case IIO_CHAN_INFO_SCALE:

		if (rescale->chan_processed) {

			/*

			 * Processed channels are scaled 1-to-1

			 */

			*val = 1;

			*val2 = 1;

			ret = IIO_VAL_FRACTIONAL;

		} else {

			ret = iio_read_channel_scale(rescale->source, val, val2);

		}

		switch (ret) {

		case IIO_VAL_FRACTIONAL:

			*val *= rescale->numerator;
@@ -130,16 +148,27 @@ static int rescale_configure_channel(struct device *dev, 
	chan->ext_info = rescale->ext_info;

	chan->type = rescale->cfg->type;



	if (!iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) ||

	    !iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE)) {

		dev_err(dev, "source channel does not support raw/scale\n");

	if (iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) ||

	    iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE)) {

		dev_info(dev, "using raw+scale source channel\n");

	} else if (iio_channel_has_info(schan, IIO_CHAN_INFO_PROCESSED)) {

		dev_info(dev, "using processed channel\n");

		rescale->chan_processed = true;

	} else {

		dev_err(dev, "source channel is not supported\n");

		return -EINVAL;

	}



	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |

		BIT(IIO_CHAN_INFO_SCALE);



	if (iio_channel_has_available(schan, IIO_CHAN_INFO_RAW))

	/*

	 * Using .read_avail() is fringe to begin with and makes no sense

	 * whatsoever for processed channels, so we make sure that this cannot

	 * be called on a processed channel.

	 */

	if (iio_channel_has_available(schan, IIO_CHAN_INFO_RAW) &&

	    !rescale->chan_processed)

		chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW);



	return 0;